Three exact retention rows show repeated multiplication without a continuous decay law. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Retention one loses no amplitude
Initial amplitude 8 m multiplied by retention 1 for 3 cycles leaves 8 m and loses 0 m.
An=8(1)3=8m,L=0m
Half retention leaves one metre after three cycles
Initial amplitude 8 m multiplied by retention 1/2 for 3 cycles leaves 1 m and loses 7 m.
An=8(21)3=1m,L=7m
Three-quarter retention keeps a fractional remainder
Initial amplitude 8 m multiplied by retention 3/4 for 3 cycles leaves 27/8 m and loses 37/8 m.